Hectob amphion



Patented Mar. 27, 1928. i

HECTOR AMPHIONEBATTALIOU OFCAPE TOWN CAPEPROVINOE, SOUTH." AFRIGAiROAD-MAKING MATERIAL.

No Drawing.

The modern ractice'ofmacadamizing roads makes suc WOI'kRll enormous itemin the municipal and Gdvermental expendi-' ture of all countries. Thehighly ClGStI'IlCtlVQ 5 action of modern motor traffic requires amaximum of binding ispower in connection with all inacadahiizingoperations; The binder hBIGlII set out results in tremen(lOUSCOUSOlldfitlOD and givesa swift and per 100 This is a new'combination,the result of experiment and analysis and .varying betweenthe percentages hereinafter "set out. The above combination when puttogether from thei raw materials producestthe above eifects.

The above composition vmayvary in practice within certain maxima andminima per centages subject to slight loss Ofelficiency ashreinafteriset out. i

The-quartz sand set out above at the ideal percentage of 37%,may vary inpractice between 45%.and 30%,) The result of an excess of quartz sandover and above? 45% is to makethe composition too hard with failure tosecure uniformity of mixture, resulting in lack of adequateconsolidation, and lack of binding power. Itmusthere be especially notedthat of-all dangersdue to excessive variation from the ideal asabove setout; the danger caused byanincrease in the percentage of "quartz sand isthe most serious to efii ciency. And for thisv purpose it advisable,except under quite exceptional circumstances, not to exceed a totallof40%. I If less than 30% of quartzsand-is: used, the compositionlosestoomuch of 'itswcapacity for mechanical frictiongrip on the sidesof the stones forming the macadam, and the petrification ultimately"set'up *bythe inter- Application flled l'anuary ll, 1924. Serial No.686,201.

action between the ca rbonatc of calcium and the quartz sand will bedefinitely lessened, and the composition will lose in toughness,effectiveness and durability.

The carbonate of calcium set out above at the ideal percentage; of 35%may vary in praetice between 42% and 32%. The carbonate of calciumpermits of less variation *inquantity relative to its total percentagethan the oxide of iron and in practice the percentages should be limitedrather more carefully between 4i0% and 35% in order to be certain ofefficiency. If the carbonate of calcium. is reduced proportionately withthe oxide of iron, this leaves too large a proportion of the remainingconstituents. If the oxideof iron is used in a higherpercentage than20%, this tends to give excessivepenetration and slight dessication ofthe carbonate of calcium by the oxide of iron, with a lossnf toughnessand resiliency. The converse observation as to the simultaneous increaseof the carbonate of calcium obtained is that the total amount of the remaining materials would then he too small. Thefundamental objection toany increase of brittleness orloss of resiliency as above set out isthat the road would then Wear much quicker than When the limits ofelliciency between 20% and 10% areobserved.

Theoxide of: ironset out above at the ideal percentage of 15% may varyin practice bctwcen20% and 10%, but these variations from the ideal ineither direction tend to sacrifice thatinherent toughness of thecomposition contributcd to it by the oxide of iron: If these margins areexceeded in either direction, definite excessive brittleness sets in. Inthecase Where oxide of iron islessthan 10% of the mixture, it becomes inoperation too brittle by reason oftoo large a comparative quantityofcarbonate of calcium. The "same relative comments as tothdratiosof thecarbonate of calcium and the oxide of iron apply here as set out above,Wl.13l1,0f course, the incidence of these comments reversed.

It is an essential portion of this invent-ion that the sum total of thequartz sand and the carbonate oi calciumshould, as a joint contributionto the composition, not exceed 00% and not less than 45%. exceedyitwould have to be at the expense of either the silicate of aluminium orthe quartz Should. they sand, an undue absence oi either oi which wouldhave results indicated hereinafter. On the other hand, if the carbonateof calcium and the oxide of iron are present in less quantity thesimilar results indicated hereinafter caused by excess of the quartzsand or the silicate of aluminium would result. As to the generalproportions of the oxide of iron and the carbonate of calcium, each toeach, the latter should exceed the former by not less than twice thequantity nor more than four times, but in either case, as alreadystated, variation from the ideal will give a slight, although within thelimits indicated, anot very material decrease in efliciency.

Silicate of aluminum set out above at the ideal percentage of 12% mayvary in practice between 22% and 7%. The result of exceeding 22% in thiscase is that a tendency to crack, to undue plasticity and to undueretardation of consolidation develops. The result of putting in lessthan 7% is that the composition loses both in compressibility andcompactness with the resulting loss of consolidating strength.

The carbon which is present in a relatively small quantity in thiscomposition and which is set out above at the ideal percentage of 1% mayvary from to 2%. It must be amorphous and finely divided. More than 2%would result in a distinct loss of hardening efiect. The absence of thecarbon would result in delay in the consolidating action. The use ofcarbon in any other form interferes with the process ofrecrystallization that occurs when the above composition is put intopractical application with water, but amorphous carbon is too soft tocause such interference.

This composition for its best practical application in the ideal formrequires reduction to a fine powder, but consolidation sufficient forpractical purposes can be obtained under the following circumstances.The quartz sand must not be crushed more than to a minimum of inch or itwill lose its frictional and interloekingvalue. The rest can vary from 4inch downward but inch is best for the whole composition as this willinclude in practice a considerable percentage of the other constituentsactually reduced to powder.

To sum up, the invention a combination of well known materialsconforming as a result of selection, quantitative analysis andcalculation with the ideal composition above set out within the limitsof variation above indicated.

This composition slightly deadens the noise usually associated with amacadamized road. The only. condition with regard to the macadam usedwith this composition is that it shall not be capable of latentdeterioration. In other words, any ordinary sound macadam will do.

A further feature of the invention consists in the process by which thiscomposition is used in practice. The best result is obtained as follows.

Upon and all over the surface of the proposed road which has beenroughly rolled after the ordinary levelling and rough smoothing requiredfor the road, and of course only where the surface is not bog orotherwise unsuitable in its entirety for roadmaking or construction, alayer of m of the composition is laid. This is covered by some 4: inchesto 4 inches of nnmulain with a maximum in case of need, of ti inches.

In practice 4 inches should not he exceeded. This is rolled and anotherlayer of of the composition is spread over the top. This is then wateredand rolled again, watered and rolled again, and any surface faults of anobvious nature tilled up with a little more of the composition. Thisroad can be used within twelve hours having initial binding to hold thecamber against heavy street traliic. This binding will increase withtime during which it will ill]- prove with trafiic. The results of thismethod are as follows:

The water will saturate the ll'ltlCiltltllll from the top down carryingwith it an intimate mixture of the composition laid above the macadam.On reaching the lower layer of the composition, it in part will drawthis up to meet the upper layer, and carrying on downward will takeportions of the lower layer into all. latent fissures,eonsolidatingevery crack, weakness or hole in the lower or natural road prior to thearrival of traffic thereon. This system will tl1ercfore prevent creepingdownhill of the finished roadway; prevent any lateral creeping away fromthe artificial hill or crown of the camber, consolidating such raw ornatural. crown underneath; provide a firm lower base which willeffectually prevent the dropping out or displacement of the lower stonesin the ma -adam by presenting to them a hard and solid foundation notpenctrable by them; prevent any movement of any maeadam stone whotsoeverin the mass as laid, giving adequate support to all such points ofindividual stones in the macadam as would otherwise be calculated tocrush under the vibration of heavy tratlic, and ultimately to causesubsidence and surface potholes.

Owing to the margin required for consolidation of the ground below thelower layer of the composition (consolidation of which acts as afoundation, without extrav expenditure, for the whole structure) thelower inch of the COll'lPOSltlOll cannotbe relied upon to rise under theinfluence of the water, except under an exceptionally heavy roller, morethan 2 inches, wherefore 4 inches is the maximum for best results. Thismeans that if 8 inches or 9 inches of macadam is required to be used,the surplus of macadam over 4 inches must be put on as a second layerabove the second layer of the composition and a third layer of thecomposition must be superimposed thereon. In practice, one layer of 4inches of macadam laid with two layers of the composition as above setout, will be enough save in exceptional cases.

The characteristic features of the present invention are (1) thediscovery of a new synthetic combination of Well known ma terialsreadily obtainable, which combination conforms with the percentagesabove set out within the limits indicated and which, after reduction toa powder within the limits above set out and mixed and applied to roadsas above set out, results in a hard, insoluble, consolidating, cementingmass, in other Words, the discovery of a new and improved binder; and(2) a simple process of applying the said composition in layers so as toform not only a tough, resilient and tenacious road but also a securefoundation therefor.

What I claim is:

1. A binding material for macadam, comprising a mixture of approximately37 per cent sand, per cent calcium carbonate, 15 per cent iron oxide,and 12 per cent aluminum silicate, all the ingredients being in the formof particles not exceeding 4, inch in greatest dimension.

2. A composition for the construction of roads and like surfaces,comprising a mixture of at least 37 per cent quartz sand, about 35 percent calcium carbonate, about 12 per cent aluminum silicate, and ironoxide in sufficient quantity to make with the calcium carbonate not morethan 60 per cent nor less than per cent of the mixture.

3. A composition according to claim 2, wherein the quartz sand is in theform of particles not exceeding inch in greatest dimension.

4. A composition for the construction of roads and like surfaces,comprising a mixture of about 37 per cent fine aggre ate, about 35 percent calcium carbonate, a out 12 per cent aluminium silicate, and about15 per cent iron oxide.

5. A composition for the construction of roads and like surfaces, comrising a mixture of about 37 per cent hne aggregate, about 35 per centcalcium carbonate, about 12 per cent aluminum silicate, iron oxide insuflicient quantity to make with the calcium carbonate not more than 60per cent nor less than 40 per cent of the mixture, and about 1 er centamorphous carbon.

ln testimony whereof I have signed my name to this specification.

HECTOR AMPH ION BATTALIOU.

